Help Stop The Roll!

[veloce200 3]

come to think about it, i have seen plenty of race 205s that were higher at the front than the rear

 

exactly... goes against all conventional wisdom but there are reasons for it..

 

see if you can spot any wheels lifting....photos

[jonah 1]

lowering the car so the wishbones are below parallel drops the front roll centre way below ground from it's initial location above ground (this is an inherent problem with MacStrut) whilst this lowers static CofG in a corner the roll centre moves dramatically and there is more leverage (the distance between so even stiff springs cannot prevent greater body roll. I'm not going to write an essay explaining it. I have given customers this advise before and they all agreed it worked. I would suggest John tries it. It's not just about CG height it's front and rear roll couples. You will NEVER see a production car with Mac Strut wishbones pointing up. With double wishbone it s a different story altogether. Why do you think people move pick up points for racing?

Ok I admit to not knowing enough about roll couple / roll centres to understand that properly... but I can see your point from a static forces point of view. If the wishbones are sloping upwards, then any lateral force through them results in a vertical component that tries to the compress the spring on the outer wheel and extend the inner. So yes, I agree that would add to the weight transfer and increase roll.

 

Think I should go and read up on this stuff...

[Jonmurgie 2]

see if you can spot any wheels lifting....photos

Well I can say the same about Cadwell mate so that proves nothing for me I'm affraid: http://www.trackphoto.co.uk/car.php?DIR=20.../H490OKG&PAGE=1

 

And here is how the car is sitting front/rear height:

 

Now in my eyes that's not a low car...

[veloce200 3]

Well I can say the same about Cadwell mate so that proves nothing for me I'm affraid: http://www.trackphoto.co.uk/car.php?DIR=20.../H490OKG&PAGE=1

 

And here is how the car is sitting front/rear height:

 

Now in my eyes that's not a low car...

 

I didn't say it was low as in slammed - I just know that mine is higher than yours at the front and my wishbone is dead parallel. Have you looked at the wishbone angle? a few mm makes all the difference. i'm only trying to help!!! ps Picture 4815 - rear wheel off the ground...!!! my suggestion is free and easy to do - why not try it ?

Edited April 12, 2006 by veloce200

[jonah 1]

Reucing the rear ARB thickness will certainly allow the inside rear wheel to droop but as there is no weight on it to give grip, what's the point?

The reason I was thinking of was to keep the it on the ground for as long as possible at lower lateral-g forces, to make the amount of roll more linear with the cornering load. I can imagine that at the moment it stays very level up to a point, then suddenly starts to lean over once the inside rear starts to lift, with the associatied sudden rate of change of camber / weight distribution at the front. Softening the rear would make the body roll more progressive and maybe iron out any handling quirks if there were any.

 

I can think of reasons not to do this as well though so it depends what problem you're trying to address...

 

As I say I don't really notice that it cocks a leg in a corner as it doesn't seem to through the car off balance or anything?!

 

In that case... what aspect of the driving experience are you trying to improve? Is the roll itself such a bad thing or is there another effect caused by the roll that you want to cure? (I'm not having a go in case it sounds like that, just looking at things from a different perspective)

 

(edit: sorry, just realised you've already answered that!)

Edited April 12, 2006 by jonah

[veloce200 3]

if you look at pics of mine and jons car his does appear to roll more...

 

FRONT jons 275 lb mine 250lb

REAR jons - 23torsion 25mm arb mine - std torsion/bumpstop dampers/ 23 mm arb

 

so if I have less roll stiffness you would have thought it would roll more but it doesn't ? (although he was going faster due to A048's so this is a factor)

Edited April 12, 2006 by veloce200